Printer with dynamic security feature. Some HP printers are designed to work only with cartridges that contain new or reused chips or electronic circuits from HP. These printers use dynamic security measures to block cartridges that have a non-HP chip or a non-HP electronic circuit. Regular firmware updates maintain the effectiveness of these measures and can block cartridges that previously worked. Reused HP chips and electronic circuits from HP allow the use of reused, remanufactured, and refilled cartridges.